Transcript RAD 254 Digital Imaging

RAD 254 Digital Imaging
Basic Elements of Digital Imaging
CR/DR
CD/DR
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Image data CAPTURE
Image data PROCESSING
Image DISPLAY
Image data ARCHIVING
Image data DISTRIBUTION &
TRANSMISSION
Electronic Imaging
• Produce image
– Digitize (A-D Converter)
• Process Data
– Output or
D-A Conversion then Analog Display
» Network
» Archive Image
Image Acquisition & Detection
• Image detector types:
– COMPUTED RADIOGRAPHY (CR)
• Photostimulable Phosphor (PSP)
– DIRECT RADIOGRAPHY (DDR, “DR”)
• Solid State X-ray Detector (SSXD)
CR/DR Differences (steps)
• COMPUTED RADIOGRAPHY(CR)
– X-ray – PSP – A-D Conversion – Data
• DIRECT RADIOGRAPHY (DDR, “DR”)
– X-ray – SSXD - Data
Image Data Processing
• The selection of processing algorithms,
and anatomic regions and radiographic
projections controls how the acquired
(latent) image is presented for display
Image Display
• In both CR and DR, a separate device
MUST be used to display (as well as view)
the digitized image (video monitor)
– High resolution (1.5-2.5k matrix)
– Diagnostic
– Clinical Review
– Web based
Image Data Archiving
• Storage and retrieval
• RAID
– Storage – Terabyte (Tb) capacity
• Digital Linear Tape (DLT)
• Application Software Provider (ASP)
Image Data
Distribution/Transmission
• One of the greatest strengths of a digital
imaging system is the ability to share
images simultaneously with multiple sites,
sometimes over great distances (Iraq)
– PACS
– Teleradiology
Myth
• “DR” will turn a bad tech into a good tech!
• TRUTH – Digital radiography makes
people “stupid” = give them an “auto pilot”
mentality
Myth
• “Positioning and collimation don’t matter”
• Truth: Positioning and collimation are
MORE critical with digital imaging systems
Myth
• “X-ray techniques don’t matter – you can
use whatever you want.”
• Truth: Images almost always look better
at higher exposures – very possible to
over-expose the patient!
Caveat:
• Typically use HIGHER kVp
– Get the photons to the image receptor
– Algorithm to determine image quality
• STILL GREAT POTENTIAL TO OVER
IRRADIATE THE PATIENT
Myth
• “DR only operates as a 200 speed
system.”
• TRUTH: Can operate at whatever speed
system you desire… but remember
– NOISE vs. X-RAY DOSE
Myth
• “You can’t use grids with a CR system.”
• TRUTH: Grid use is still an important part
of obtaining good image quality and
controlling scatter
Computer Technophobia
Nagy, P
• “A Symantic study found that 70% of users
experienced difficulties with computers.
Symptoms included swearing at
computers, loss of productivity, and
emotional distress. 21% of users suffer
from ‘PC RAGE,’ sometimes involving
physical assault on and damage of a
computer.”
Skill sets NOT to forget:
• Basic Radiography 101
– Proper patient positioning
– Proper beam restriction
– Proper exposure factors
– Correct patient ID
– Correct R and L marker use
Skill sets NOT to forget:
• Basic x-ray physics
– How a radiographic image is made
– GOOD image quality elements
– Effects of incorrect x-ray exposure selection
and image quality
New Skill Set Development:
• Critical thinking skills
• Ability to identify a good image
• Knowledge of how to fix a repairable bad
image
• Understanding the exposure indicator
New Terminology
• PACS
– Picture Archival and Communications
Systems
• PPACS
– Picture and Paper and Communications
System
New Terminology
• Teleradiology
• ASP
– Application Service Providers
• DICOM
– Digital Images and COmmunication in
Medicine
• HL-7
– Health Level - 7
New Terminology
• HIS
– Hospital Information System
• RIS
– Radiology Information System
• HIS/RIS Broker (make sure they talk to
each other)
Electronic Medical Record (EMR)
• DICOM Standard
» Work Stations
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HL-7 Standard
21st Century Imaging
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All modalities will be in digital format
Direct to Digital acquisition (SSXD)
On-line access to patient records
“Total” patient record (EMR)
Software and equipment changes
Radiation exposure a MAJOR concern
Remote reading stations miles away
STOP the BS and just tell me!
• In CR – the photostimulable phosphor (just like
an intensifying screen) is exposed to x-rays. The
PSP cassette is then “scanned” by a laser
“reader” to obtain the image (stored images are
released as varied shades of “light”)
• DR/DD uses a “flat panel detector(s) and a
scintillator combined with a photodiode the light
produced is “digitized” and translated into
“densities” for computer viewing.
Thanks to:
• Rolando R. Reyes, B.S., R.T.(R)
– Senior Project Manager
– Eastman Kodak Health Imaging
– Rochester, NY